Integration of ceramic membrane into a silicon oxide production plant

Abstract

An integrated system for producing high purity silicon dioxide comprising: a) a source of an oxygen-containing feed gas containing at least one impurity, b) an oxygen transport membrane cell containing an oxygen-selective transport membrane that has a cathode side and an opposing anode side, the membrane being at an elevated temperature effective for separation of oxygen in the feed gas from the impurity by transporting oxygen ions from the oxygen-containing feed gas through the membrane to the anode to form a purified oxygen permeate on the anodeside, while retaining an essentially oxygen-depleted, impurity-containing retentate on the cathode side, c) a passageway from the source (a) to the cathode side of the membrane cell, d) a silicon source, and e) a silicon oxidation furnace, in communication with the anode side of the membrane cell, for reaction of the purified oxygen permeate with silicon from the silicon source, at an elevated reaction temperature effective for the reaction, in order to produce the high purity silicon dioxide.

What is claimed is:  
     
       1. An integrated system for producing high purity silicon dioxide comprising: 
       a) a source of an oxygen-containing feed gas containing at least one impurity,  
       b) an oxygen transport membrane cell containing an oxygen-selective transport membrane that has a cathode side and an opposing anode side, said membrane being at an elevated temperature effective for separation of oxygen in said feed gas from said impurity by transporting oxygen ions from said oxygen-containing feed gas through said membrane to said anode to form a purified oxygen permeate on said anode side, while retaining an oxygen-depleted, impurity-containing retentate on said cathode side,  
       c) a passageway from said source (a) to the cathode side of said membrane cell,  
       d) silicon wafers, and  
       e) a silicon oxidation furnace, in communication with said anode side of said membrane cell, for reaction of said purified oxygen permeate with silicon from said silicon wafers, at an elevated reaction temperature effective for said reaction, in order to produce said high purity silicon dioxide.  
     
     
       2. The integrated system of  claim 1  which additionally comprises: 
       (f) a heating source for providing said elevated temperature of (b) and said elevated reaction temperature of (e).  
     
     
       3. The heating source of  claim 2  which is selected from the group consisting of resistive heaters, conductive heaters, convection heaters, and combinations thereof. 
     
     
       4. The integrated system of  claim 1  additionally comprising an inlet tube for transmitting said feed gas to said membrane. 
     
     
       5. The integrated system of  claim 1  additionally comprising an exhaust port for transmitting exhaust gas from said furnace. 
     
     
       6. The integrated system of  claim 1  wherein said oxygen-containing feed gas is air, wherein said impurity comprises nitrogen, and wherein said retentate comprises nitrogen. 
     
     
       7. A process for producing a pure silicon dioxide coating on a substrate comprising contacting a surface of the substrate with silicon dioxide produced using the integrated system of  claim 1 . 
     
     
       8. A method for preparing high purity silicon dioxide comprising the steps of: 
       a) feeding an oxygen-containing feed gas into a cathode side of an oxygen transport membrane cell containing said cathode side and an anode side, with an oxygen transport membrane therebetween,  
       b) selectively transporting oxygen ions from said oxygen-containing feed gas from said cathode side through said membrane to said anode side to provide a purified oxygen permeate,  
       c) reacting said purified oxygen permeate with silicon of silicon wafers located in a silicon oxidation furnace to form said high purity silicon dioxide.  
     
     
       9. The method of  claim 8  wherein step b), is effected at an elevated temperature of from about 450 to about 1200 degrees Centigrade. 
     
     
       10. The method of  claim 8  wherein step c) is effected at an elevated temperature of from about 450 to about 1200 degrees Centigrade. 
     
     
       11. The method of  claim 8  wherein steps b) and c) are each effected at an elevated temperature provided by heat from a heating source selected from the group consisting of resistive heaters, conductive heaters, convection heaters, and combinations thereof. 
     
     
       12. The method of  claim 8  wherein step b) is effected in a pressure drive mode whereby said oxygen ions are transported from said cathode side through said membrane to said anode side by means of a lower oxygen partial pressure at the anode side of the membrane relative to that at the cathode side. 
     
     
       13. An integrated system for the delivery of high purity oxygen to a silicon oxidation furnace and for using the high purity oxygen to prepare high purity silicon dioxide comprising: 
       a) an oxygen transport membrane cell containing an oxygen selective ion transport membrane that has a cathode side and an opposing anode side and is at a temperature effective for the transport of oxygen ions from said cathode side to said anode side,  
       b) an oxygen-containing feed gas contacting said cathode side wherein oxygen ions from said feed gas are transported to said anode side to provide an oxygen permeate, and an oxygen-depleted retentate is retained as an effluent stream on said cathode side,  
       c) reacting a reaction mixture comprising said oxygen permeate and silicon from silicon wafers located in a silicon oxidation furnace heated to an elevated temperature sufficient to react the reaction mixture, thereby forming said high purity silicon dioxide.  
     
     
       14. The integrated system of  claim 13  additionally comprising a heating source selected from the group consisting of resistive heaters, conductive heaters, convection heaters, and combinations thereof. 
     
     
       15. The integrated system of  claim 13  wherein the ion transport membrane comprises a mixed oxide perovskite material. 
     
     
       16. The integrated system of  claim 13  wherein said elevated temperature is in the range of from about 900 to about